For many people who lost relatives that night the last two years have been a long search for answers on how the accident could have been prevented.
Tonia White, whose parents Tony and Pamela Adams were killed in the crash, is now campaigning for tighter legislation on fireworks displays.
An explosives expert tells an inquest he has been unable to find any literature warning of the dangers of smoke from fireworks to drivers.
Drivers have told an inquest of their horror at being involved in one of the worst British motorway pile-ups in living memory.
Witnesses have been describing the driving conditions at the inquest into the deaths of seven people who died after a pile-up on the M5.